The background of the invention will be discussed in two parts:
1. Field of the Invention
This invention relates to bicycle brakes and more particularly to a bicycle brake assembly having a hollow elongate stem affixed relative to the brake lever, which may be a caliper or a cantilever brake member, and a brake pad attachable thereto by a bolt extending through the opening. One end of the stem and the adjoining portion of the pad are matingly configured for providing a fixed orientation of the pad relative to the brake lever on the replacement of the pad.
2. Description of the Prior Art
Modern bicycles have brake assemblies mounted to the forks and frame for gripping of the rim in response to operator manipulation of brake levers. Such brake assemblies generally include brake shoes, which are movably mounted on brake lever assemblies, such as caliper assemblies which bridge the rim, or cantilever brake levers which attach to the forks on opposite sides of the rim. Such brake shoes have a brake pad of friction material for abuttingly and frictionally engaging the rim for slowing or stopping of the bicycle. The majority of such brake shoes are formed of a brake pad with an integrally formed fastening threaded shaft, with the pads typically molded about a metal member formed integrally with, or securely attached to, the stem.
For attachment to the caliper or brake lever, the stem is inserted through an aperture in the end of the lever with the pad in a position adjacent the rim, and a nut, or other suitable fastener is usually threaded to the other end of the stem to maintain the pad in a position adjusted relative to the rim. However, when replacing the pads, which may be done for reasons other than wear, this necessitates readjustment or realignment of the pad relative to the rim. Modern cyclists may replace the pads for different weather conditions, such as one set on pads for rain, another for dry, or other reasons, such as to provide clearance for flat tire removal of large tires such as mountain bike tires. The time involved in realignment may become critical, particularly if a brake shoe is being replaced during a race or other contest.
One such prior art brake shoe assembly is shown in FIG. 1, wherein there is shown in phantom illustration a bicycle rim 10, a cantilever brake arm, generally designated 12, and a brake shoe, generally designated 14. The brake shoe is a generally T-shaped member, having a threaded stem or shaft portion 14a and a generally orthogonally oriented elongate brake pad 14b. The brake arm 12 is provided with a stem clamp device 12a with an aperture 12b extending therethrough, the aperture 12b having a diameter generally equal to the diameter of the shaft 14a.
The outer surface of the shaft 14a is serrated longitudinally so that upon insertion into the aperture 12b there is a generally tight frictional engagement which minimizes rotation of the shaft 14a within the aperture 12b. The inner diameter of the aperture 12b may likewise be serrated in the longitudinal direction. Although not shown, the free end of the shaft 14a may be threaded for enabling attachment of a suitable fastener, such as a nut, or the like. Upon attachment of the shoe 14, the pad 14b is aligned relative to the rim 10 by positioning prior to insertion of the shaft 14, with readjustment often requiring repeated withdrawals and re-insertions. Consequently when brake shoes are replaced, a considerable amount of time may be wasted.
It is a feature of the present invention to provide a new and improved brake shoe assembly which virtually eliminates the need for realignment on pad replacement.